Sepherosa Ziehau is switching a number of network cards over to use ifpoll, which means they will have capabilities similar to MSI-X, even if the network card doesn’t support it.  My suspicion is that it will make these cards perform better in busy situation where they would otherwise get bogged down… but that’s based on hunch rather than empirical testing.  As Sepherosa Ziehau pointed out, it certainly can’t hurt.